Substituted ammonium salt of 1,5′-bitetrazole

ABSTRACT

The 1,5′-bitetrazole of the invention comprises 1,5′-bitetrazole, and ammonia or an amine. The 1,5′-bitetrazole of the invention decomposes sharply and generates a nontoxic gas.

BACKGROUND OF THE INVENTION

The present invention relates to novel 1,5′-bitetrazole compounds and processes for their production.

The present invention also relates to gas generating agents containing the 1,5′-bitetazole compounds.

The present invention further relates to foaming agents for precision molding of resins, foaming agents for reducing weight of molded articles, smoking agents for effectively diffusing chemicals such as agricultural chemicals or insecticides, and air bag gas generating agents.

It is difficult td mold crystalline resins into the shape defined by a mold, since they crystallize and shrink upon cooling after molding. Conventionally, for precision molding of crystalline resins, apparent shrinkage is empirically inhibited by using specially devised molds, which, however, cannot accomplish complete precision molding. Accordingly, additional techniques for further reducing shrinkage of molded articles are employed, which include physical blowing of gas into the core portion of molded articles (Japanese Examined Patent Publications Nos. 41264/1973 and 14968/1982), and addition of chemical foaming agents (Japanese Unexamined Patent Publications Nos. 129563/1975, 12864/1978 and 61435/1981, and U.S. Pat. No. 4,871,861). In conventional techniques, azodicarbonamide (ADCA) has been used widely for a long period of time, mainly for foam molding of resins.

ADCA, although utilized widely as a gas generating agent, is not wholly satisfactory for use in precision molding or high-foam molding for weight reduction, because it has too broad a decomposition temperature range relative to the molding temperature and causes air bubbles on the surface of molded articles, which impair the appearance. Moreover, decomposition gases and residues of ADCA contain toxic substances such as ammonia, biurea or isocyanuric acid, and thus are harmful to humans and animals and the environment. Further, the decomposition residue contaminates molds, decreasing the molding efficiency and yield of molded articles.

To solve the above problems, use of tetrazoles as gas generating agents was proposed. Tetrazoles, which decompose completely, are free from the above problems. However, since high decomposability means low stability, tetrazoles are highly sensitive to friction or other physical factors, lacking handling safety.

Further, although air bag gas generating agents and smoking agents are required to be harmless to humans and animals, safe, and odorless, conventional air bag gas generating agents and smoking agents do not fully satisfy these requirements.

SUMMARY OF THE INVENTION

An object of the invention is to provide a novel 1,5′-bitetrazole compound which is highly sensitive only to temperature and which decomposes sharply, i.e., decomposes in a narrow temperature range, and generates a nontoxic gas.

Another object of the invention is to provide a gas generating agent which is highly sensitive only to temperature and which decomposes sharply and generates a nontoxic gas.

The present inventors did extensive research to achieve the above objects and directed their attention to 1,5′-bitetrazole which leaves substantially no residue upon decomposition. They found that ammonia or amine can be used to reduce the physical sensitivities of 1,5′-bitetrazole. The present invention has been accomplished based on this novel finding.

The present invention provides the following 1,5′-bitetrazole, processes for their production, and gas generating agents containing the.

1. A 1,5′-bitetrazole represented by the formula (1):

wherein Tz³¹ represents

R¹, R² and R³ are the same or different and each represent a hydrogen atom; C₁₋₁₀ alkyl which may be substituted by amino, di(C₁₋₄ alkyl)amino, C₁₋₈ alkoxy, hydroxy or phenyl; C₃₋₂₀ alkenyl; phenyl; —C(═NH)NH₂; —C(═NH)NHNH₂; —C(═NH)NHCN; triazolyl; amino; carbamoyl; triazinyl which may be substituted by amino and methyl; —NHCS;

or —R⁴—NH₃ ⁺ Tz⁻ wherein Tz⁻ is as defined above, R⁴ represents a single bond, C₂₋₆ alkylene, phenylene, —CO— or

when R¹ is a hydrogen atom, R² and R³ may be taken together with the nitrogen atom to which they are attached to form a 5- to 7-membered saturated heterocycle; when R¹ is a hydrogen atom, R² and R³ may be taken together to form

and R¹, R² and R³ may be taken together to form

2. A process for producing a 1,5′-bitetrazole amine salt according to Item 1 comprising the step of reacting 1,5′-bitetrazole or its alkali salt with ammonia or an or its carbonate or halide, the amine being represented by the formula:

R⁵R⁶R⁷N  (2)

wherein R⁵, R⁶ and R⁷ are the same or different and each represent a hydrogen atom; C₁₋₁₀ alkyl which may be substituted by amino, di(C₁₋₄ alkyl)amino, C₁₋₈ alkoxy, hydroxy or phenyl; C₃₋₂₀ alkenyl; phenyl; —C(═NH)NH₂; —C(═NH)NHNH₂; —C(═NH)NHCN; triazolyl; amino; carbamoyl; triazinyl which may be substituted by amino and methyl; —NHCS;

or —R⁸—NH₂ wherein R⁸ represents a single bond, C₂₋₆ alkylene, phenylene, —CO— or

when R⁵ is a hydrogen atom, R⁶ and R⁷ may be taken together with the nitrogen atom to which they are attached to form a 5- to 7-membered saturated heterocycle; when R⁵ is a hydrogen atom, R⁶ and R⁷ may be taken together to form

and R⁵, R⁶ and R⁷ may be taken together to form

3. A gas generating agent containing a 1,5′-bitetrazole according to Item 1.

4. A foaming agent for molding resins, which contains a 1,5′-bitetrazole according to Item 1.

5. An air bag gas generating agent containing a 1,5′-bitetrazole according to Item 1.

6. A smoking agent for diffusing chemicals, which contains a 1,5′-bitetrazole according to Item 1.

The 1,5′-bitetrazole amine salt of the invention comprises 1,5′-bitetrazole, and ammonia or an amine.

Useful amines include monomethylamine, monoethylamine, n-propylamine, isopropylamine, n-butylamine, sec-butylamine, t-butylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine, oleylamine, allylamine, 3-dimethylaminopropylamine, 3-dibutylaminopropylamine, 3-methoxypropylamine, 3-ethoxypropylamine, 2-ethylhexyloxypropylamine, methyliminobispropylamine, cyclohexylamine, aniline, benzylamine, phenethylamine, dicyandiamide, guanidine, aminoguanidine, aminotriazole, monoethanolamine and like primary monoamines; ethylenediamine, hexamethylenediamine, phenylenediamine, xylenediamine, xylylenediamine, acetoguanamine, hydrazine, urea, carbohydazide, thiocarbohydrazide, N-acetyl-m-phenylenediamine, 2,4-diamino-6-methyl-symtriazine, 1,4-bis(3-aminopropyl)piperazine and like primary diamines; melamine and like primary triamines; dimethylamine, diethylamine, dicyclohexylamine, di-2-ethylhexylamine, diethanolamine, piperazine, piperidine, diphenylamine and like secondary monoamines or secondary diamines; and trimethylamine, triethylamine, N,N,N′,N′-tetramethylethylenediamine, hexamethylenetetramine, pyridine, N,N-dimethylaniline, N,N-dimethylcyclohexyl-amine, triethanolamine and like tertiary amines.

The process for producing the novel 1,5′-bitetrazole of the invention comprises the steps of dissolving 1,5′-bitetrazole or its alkali metal salt in water, an alcohol (preferably a C₁₋₃ alcohol) or dimethylformamide (DMF), and adding ammonia or the above amine or its carbonate or halide in an equivalent amount relative to the 1,5′-bitetrazole or its alkali metal salt, followed by stirring. When an alkali metal salt of 1,5′-bitetrazole and an amine halide are used, it is preferable to select such a combination that the alkali metal halide produced as a byproduct is soluble in water, alcohol or DMF, so that 1,5′-bitetrazole can be easily obtained by collecting crystals by filtration.

The reaction is carried out at preferably 0 to 100° C., more preferably 20 to 60° C., for a period of preferably 0.5 to 10 hours, more preferably 1 to 3 hours.

The 1,5′-bitetrazole is a novel substance which has low detonability and high stability against physical shocks, i.e., low sensitivity to impact or friction. Unlike ADCA, the 1,5′-bitetrazole is free from the problems of toxic decomposition gas or residue, since it decomposes completely and generates a nontoxic gas. Therefore, it is usable as an air bag gas generating agent or a smoking agent. Moreover, since the compound decomposes sharply, its use as a foaming agent, for example in injection molding, enables formation of a smooth skin layer which cannot be obtained by use of ADCA or like substance, and achieves precision molding free from sinkmarks or warpage.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the result of differential thermal analysis of 1,5′-bitetrazole guanidine salt as an embodiment of the invention.

FIG. 2 shows the infrared absorption spectrum of 1,5′-bitetrazole guanidine salt as an embodiment of the invention.

FIG. 3 shows the result of NMR analysis of 1.5′-bitetrazole guanidine salt as an embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The following examples are intended to illustrate the present invention in further detail.

EXAMPLE 1

A 500-ml, four-necked flask equipped with a stirrer and thermometer was set in an oil bath and charged with 50 g (0.362 moles) of 1,5′-bitetrazole (molecular weight: 138.09), followed by addition of 300 ml of water. The mixture was heated to 40° C., and 15.6 g (0.181 moles) of piperazine (molecular weight: 86.14) was added with stirring. Simultaneously with addition of the piperazine, crystals formed and the reaction mixture became pale yellow. The reaction mixture was cooled to room temperature with stirring, and subjected to suction filtration using a No. 2 filter paper, whereby 1,5′-bitetrazole piperazine salt (molecular weight: 362.32) was obtained in a yield of 85%.

EXAMPLE 2

2 g of 1,5′-bitetrazole was measured out into a 50-ml beaker, and dissolved by addition of 50 ml of methanol. 0.87 g of saturated aqueous ammonia was added, followed by thorough stirring. The methanol was allowed to evaporate to collect crystals, which were then washed with acetone and analyzed.

EXAMPLE 3

2 g of 1,5′-bitetrazole was measured out into a 50-ml beaker, and dissolved by addition of 50 ml of methanol. 10 ml of water and 1.37 g of benzylamine were added in this order. Crystals formed were collected and washed in the same manner as in Example 2, dried and analyzed.

EXAMPLE 4

1,5′-bitetrazole were obtained using amines other than those used in Examples 1, 2 and 3 and following the procedure of Example 1, 2 or 3.

EXAMPLE 5

The 1,5′-bitetrazole obtained in Examples 1 to 4 were subjected to determination of melting point and decomposition temperature, elementary analysis, infrared absorption analysis, and NMR analysis. The results are shown in Tables 1 to 8.

In the column of “decomposition” in Tables 1 and 2, “sharp” indicates that the decomposition occurred in a narrow temperature range, while “broad” indicates that the decomposition occurred over a broad temperature range.

TABLE 1 Melting Point and Decomposition Temperature Primary Amine Salt De- comp. Boiling Point/ M.P. Temp. Sublimation Temp. Decom- Amine salt (° C.) (° C.) (° C.) position 1,5-BHT.H₂O — 148 sharp Ammonium — 185 sharp Monomethylamine 159 170 sharp Ethylamine 123 176 broad n-Propylamine — 206 sharp Isopropylamine — 218 258 broad sec-Butylamine 168 197 broad t-Butylamine 145 187 broad n-Hexylamine — 181 sharp n-Octylamine 93 185 broad 2-Ethylhexylamine 85 185 broad Oleylamine 91 188 broad Allylamine — 209 sharp Cyclohexylamine 159 189 broad Monoethanolamine 125 169 sharp Aniline 132 206 broad Benzylamine 135 185 broad Phenethylamine 155 186 broad Guanidine 187 189 sharp Aminoguanidine 174 177 sharp Dicyandiamide — 201 sharp 3-Amino-1H- — 167 sharp 1,2,4-triazole Ethylenediamine — 185 sharp Hexamethylenediamine 141 172 sharp m-Phenylenediamine — 201 233 broad m-Xylylenediamine 166 186 broad Hydrazine 144 178 broad 1-Urea 131 149 217 broad 2-Urea 119 151 215 broad Thiocarbohydrazide 141 194 sharp Melamine 1/3 190 255 311 broad Melamine 2/3 189 251 305 broad Melamine 1/1 — 256 326 broad Notes: (1) In Tables 1 and 2, “—” indicates that no clear melting point was found by the determination. (2) “1,5-BHT” indicates 1,5′-bitetrazole. The same applies hereinafter.

TABLE 2 Melting Point and Decomposition Temperature Secondary and Tertiary Amine Salts De- comp. Boiling Point/ M.P. Temp. Sublimation Temp. Decom- Amine salt (° C.) (° C.) (° C.) position Dimethylamine 134 152 broad Piperazine — 205 sharp Piperidine — 183 broad Diphenylamine 140 157 broad Trimethylamine — 204 sharp Hexamethylene- 148 178 broad tetramine

TABLE 3 Elementary Analysis Primary Amine Salt C H N Cal- Cal- Cal- Amine Salt cd. Found cd. Found cd. Found 1,5-BHT.H₂O 15.39 15.42 2.58 2.52 71.78 71.25 t-Butylamine 34.12 35.57 6.20 6.24 59.68 58.63 n-Hexylamine 44.16 33.21 7.16 5.89 52.68 59.86 n-Octylamine 44.93 43.53 7.92 7.74 47.15 49.84 2-Ethylhexylamine 44.93 44.59 7.92 8.07 47.15 47.50 Oleylamine 59.23 58.88 9.69 10.12 31.08 30.64 Allylamine 30.77 29.53 4.65 4.59 64.58 63.66 Cyclohexylamine 40.50 40.81 6.37 6.48 53.13 52.39 Monoethanolamine 24.12 24.60 4.55 4.60 63.29 62.00 Aniline 41.56 41.80 3.92 4.01 54.52 54.29 Benzylamine 44.08 44.92 4.52 4.51 51.40 51.81 Phenethylamine 46.33 46.38 5.05 5.20 48.62 48.00 Guanidine 18.28 19.07 3.58 3.43 78.15 78.63 Arninoguanidine 16.98 16.75 3.80 4.11 79.22 79.77 Dicyandiamide 21.62 21.58 2.72 3.00 75.65 74.21 3-Amino-1H- 23.08 22.80 2.91 2.88 74.01 74.23 1,2,4-triazole Ethylenediamine 21.43 20.90 3.60 4.05 74.96 75.02 Hexamethylene- 37.79 36.21 7.13 7.08 55.08 55.32 diamine m-Phenylenediamine 39.02 38.68 4.09 3.81 56.88 57.01 m-Xylylenediamine 34.95 34.56 3.91 4.05 61.14 59.48 Hydrazine 15.59 15.39 2.62 2.43 81.80 82.56 1-Urea 18.19 17.85 3.05 2.93 70.69 70.76 2-Urea 18.61 18.78 3.90 3.87 65.10 66.17 Thiocarbohydrazide 15.71 15.38 2.64 3.09 73.27 71.68 Melamine 1/3 20.00 20.00 2.44 2.50 77.76 78.00 Melamine 2/3 20.90 20.17 2.51 2.60 76.60 75.80 Melamine 1/1 22.73 22.61 3.05 2.98 74.22 73.99

TABLE 4 Elementary Analysis Secondary and Tertiary Amine Salts C H N Cal- Cal- Cal- Amine Salt cd. Found cd. Found cd. Found Dimethylamine 26.23 25.37 4.95 4.50 68.82 69.07 Piperazine 26.52 26.51 3.89 4.11 69.58 68.27 Piperidine 37.66 37.43 5.87 5.97 56.47 55.97 Diphenylamine 54.72 55.85 4.26 4.11 41.02 41.57 Trimethylamine 30.45 30.17 5.62 5.49 63.92 63.15 Hexamethylene- 34.53 34.14 5.07 5.11 54.83 59.01 tetramine

TABLE 5 Infrared Spectroscopic Analysis Primary Amine Salt Amine Salt Characteristic Absorption (cm⁻¹) Ammonium νNH2856.5 Monomethyl- (N—CH3) νasCH 2879.5, νaCH 2758.0 amine (N—CH3) δasCH 1461.9. δsCH 1380.0 (—NH3+) δasNH 1544.9. δsNH 1494.7 Ethylamine (—CH3) νasCH 2999.1. (CH2) νasCH2 2912.3, νsCH2 2912.3 (—CH3) δasCH 1463.9, δsCH 1377.5 (—NH3+) δasNH 1571.9, δsNH 1491.6 n-Propylamine (—CH3) νasCH 2977.9, (CH2) νasCH2 2906.7, νsCH2 2846.9 (—CH3) δasCH 1460.0, δsCH 1380.6 (—NH3+) δasNH 1606.6, δsNH 1514.4 Isopropylamine (—CH3) νasCH 2977.9, (CH2) νasCH2 2906.7, νsCH2 2846.9 (—CH3) δasCH 1460.0, δsCH 1380.6 (—NH3+) δasNH 1589.2, δsNH 1514.4 sec-Butylamine (—CH3) νasCH 2977.9, (—CH3) δasCH 1460.0, δsCH 1387.6 (—CH—(CH3) 2) skeleton 1187.6 (—NH3+) δasNH 1589.2, δsNH 1514.4 t-Butylamine (—CH3) νasCH 2970.2. νsCH 2883.4 (—C—(CH3) 3) skeleton 1262.0, 1218.9, 964.1 n-Hexylamine (—CH3) νasCH 3002.4, (GH2) νasCH2 2979.8, νsCH2 2860.2 (—CH3) δasCH 1458.1, δsCH 1370.8, —CH2—rocking 708.1 (—NH3+) δasNH 1610.0, δsNH 1513.2 n-Octylamine (—CH3) νasCH 2954:5, νsCH2 2856.4, (CH2) νasCH2 2918.1 νasCH2 2823.6, (—CH3) δasCH 1461.9, δsCH 1376.8 (—NH3+) δasNH 1604.7, δsNH 1500.5 2-Ethylhexyl- (—CH3) νasCH2962.5, νsCH2 2871.8, (CH2) νasCH2 2931.6 amine νasCH2 2856.4, (—CH3) δasCH 1461.9, δsCH 1373.2 (—NH3+) δasNH 1618.4, δsNH 1508.2 Oleylamine (—CH3) νasCH 2952. 2, (CH2) νasCH2 2918. l, νsCH2 2850. 6 (CH3) δasCH 1463.9, δsCH 1372.1, —CH2—C═C—1435.4 (—NH3+) δasNH 1606.6, δsNH 1506.3 Allylamine (—C═CH) νCH 3023.9, (CH2) νasCH2 2919.8, νsCH2 2837.3 (—C═C—) νC═C 16.07.7, δ in plane CH 1441.4, δ out of plane CH 863.6 Cyclohexyl- (CH2) νasCH2 2935.5, νsCH2 2862.2 amine (—CH2) δCH scissors 1454.2 (—NH3+) δasNH 1591.2, δsNH 1488.0 Monoethanol- (CH2) νasCH2 2933.5, νsCH2 2879.5 amine (—CH2) δCH, scissors 1479.3 (—NH3+) δasNH 156.4, δsNH 1502.4 Aniline νCH 3047.8˜2574.8, δ out of plane CH 1967.7, 1831.3, 1751.0 1647.1 (—NH3+) δasNH 1596.8, δsNH 1498.6 Benzylamine (—CH2—) δ scissors CH 1456.2 (—NH3+) δasNH 1575.0, δsNH 1495.2 (—CH2—) νasCH 2929.7, νout of plane CH 1955.7, 18380.4, 1750.0 Phenethyl- (—CH2—) δ scissors CH 1460.0 amine (—NH3+) δasNH 1583.7, δsNH 1496.7 Guanidine νNH 3435.0˜3361.7 νC═N 1654.8 Aminoguanidine νNH 3448.5˜3260.7 νC═N 1674.1, (—NH3+) δasNH 1544.9, δsNH 1453.3 Dicyandiamide νNH 3438.8—3260.7, νC═N 2193.8, 2167.5 νC═N 1689.5, 1641.3 3-Amino-1H- νNH 3369.4˜3265.3, νC═N 1679.9, 1647.1 1,2,4-triazole (—NH3+) δasNH 1556.4, δsNH 1505.9 Ethylenediamine νNH 3456.2˜3074.3.(—NH3+) δasNH 1624.4 (—NH2—) νasCH 2943.4, νsCH 2883.4, scissors CH 1455.7 Hexamethylene- νNH 3433.0˜3026.3, (—NH3+) δasNH 1556.4, δsNH 15U5.9 diamine (—CH2—) νasCH 2935.4, νsCH 2868.0, δ scissors CH 1463.9 m-Phenylene- νNH 3476.1˜3080.1, (—NH3+) δasNH diamine 1596.8.δsNH 1498.6 νCH 3047.8˜2574.8, δ out of plane CH 1967.7, 1831.3, 1751.0, 1647.1 m-Xylylene- νCH 3448.5˜3023.9, (—NH3+) δasNH diamine 1595.7, δsNH 1504.4 (overlapped with Ph nucleus) δCH out of plane 1649.0 (—CH2—) νasCH 2918.9, νCH 2894.7, δ scissors CH 1479.3 Hydrazine νNH 3325.0˜3055.0 (—NH3+) δasNH 1610.5, δsNH 1519.8 Urea νNH 3419.6˜3095.5, (—NH3+) δasNH 1593.1, δsNH 1505.9 νC═O non—association 1697.2, νC═O association 1652.9 Thiocarbo- νNH 3211.3, (—N3+) δasNH 1527.5, δsNH 15U5.9 hydrazide νC═O non—association 1625.9 δC═S 1527.5, 1279.9, 1120.6, 931.6, 767.9 Melamine 1/3 νNH 3461.7˜3328.9, (—NH2) δ in-plane scissors NH 1668.3, 1552.6 (—NH3+) δasNH 1614.3, δsNH 1504.4 (—NH2) δ out-of-plane scissors NH 1094.5, 812.2 Melamine 2/3 νNH 3461.7˜3334.7, (—NH2) δ in-plane scissors NH 1670.2, 1554.5 (—NH3+) δasNH 1612.4, δsNH 1506.3 (—NH2) δ out-of-plane scissors NH 1095.5, 812.2 Melamine 1/3 νNH 3469.7˜3332.8, (—NH2) δ in-plane scissors NH 1664.5, 1552.6 (—NH3+) δasNH 1614.3, δsNH 1500.0 (—NH2) δ out-of-plane scissors NH 1022.7, 813.9

TABLE 6 Infrared Spectroscopic Analysis Secondary and Tertiary Amine Salts Amine Salt Characteristic absorption (cm⁻¹) Dimethylamine (—CH3) νasCH 2976.0, νsCH 2759.9, δasCH 1460.0, δsCH 1382.8 νCH 3406.7˜3026.1, (—NH3+) δasNH 1544.9, δsNH 1494.7 Piperazine (—CH2) νasCH2 2950.9, νsCH2 2862.2, δsNH scissors 1460.0 NH 3236.8, 2758.0, δNH1608.9 Piperidine (—CH2) νasCH2 2950.9, νsCH2 2862.2, δCH scissors 1428.2 νNH 2753.6, 2526.3, 1607.7 Diphenylamine νNH 3419.6, (—NH3+) δasNH 1610.5, δsNH 1519.R νCH 3091.7, δ out of plane CH 1697.2, 1652.9, Ph nucleus 1593.1 Trimethylamine (—CH2) νasCH 3004.9, νsCH2 2756.1, δasNH 1460.0, δsCH 1384.0 νNH 3398.3˜3246.8, (—NH+) δasNH 1544.9, δsNH 1494.7 Hexamethylene- νC—N 1238.1, δCH2 rocking 1008.7, 817.8, 657.7 tetramine

TABLE 7 NMR Analysis Primary Amine Salt Amine Salt (ppm) Solvent Ammonium δ9.95 (s, 1H) D₂O Monomethylamine δ9.7 (s, 1H), δ2.75 (S, 3H) D₂O Ethylamine δ9.7 (s, 1H), δ3.35-2.95 (q, 2H), D₂O δ1.5-1.25 (t, 3H) n-Propylamine δ9.0 (s, 1H) δ2.5-2.1 (t, 2H) D₂O δ1.4-0.8 (2H), δ0.6-0.3(t, 3H) Isopropylamine δ9.1 (s, 1H), δ1.0 (d, 6H).6 3.5-3.0 (1H) D₂O n-Butylamine δ9.9 (s, 1H), δ3.3 (9H) DMSO sec-Butylamine δ9.9 (s, 1H), δ1.5(t, 2H), δ1.1(d, 6H), DMSO δ3.3 (1H) t-Butylamine δ9.7 (s, 1H), δ1.4 (s, 9H) D₂O n-Hexylamine δ9.9(s, 1H), δ1.5 (13H) DMSO n-Octylamine δ9.7 (s, 1H), δ2.0-2.1 (n, 14H), D₂O δ0.8 (s, 3H) 2-Ethylhexyl- δ9.7 (s, 1H), δ2.9-3.1 (d, 2H) D₂O amine δ1.5-1.0 (m, 6H), δ0.8-1.0(m, 6H) Oleylamine δ9.7 (s, 1H), δ5.2 (s, 2H), 1.0 (s, 28H). DMSO δ0.7 (s, 3H) Allylamine δ9.9 (s, 1H), δ5.3 (t, 2H), δ5.8(1H), DMSO δ3.4 (d, 2H) Cyclohexylamine δ9.7 (s, 1H), δ3.4-3.0 (1H), D₂O δ2.2-1.0 (10H) Monoethanol- δ9.0 (s, 1H), δ3.3-3.0 (t, 2H), D₂O amine δ2.7-2.4 (t, 12H) Aniline δ9.2 (s, 1H), δ6.9 (s, 5H) D₂O Benzylamine δ9.9 (s, 1H), δ7.4 (ph, 5H), δ4.1 (s, 2H) DMSO Phenethylamine δ9.65 (s, 1H), δ7.25 (s, 5H), D₂O δ3.5-2.8 (dd, 4H) Guanidine δ9.9 (s, 1H), δ6.9 (s, 1H), D₂O δ3.35 (s, 2H) Aminoguanidine Hydrogen in amine cannot be DMSO independently determined Dicyandiamide δ9.9 (s, 1H) DMSO 3-Amino-1H- δ8.1 (s, 1H) D₂O 1,2,4-triazole Ethylenediamine δ9.7 (s, 2H), δ3.6 (s, 4H) D₂O Hexamethylene- δ9.7 (s, 2H), δ3.3-2.8 (4H), D₂O diamine δ2.1-1.3 (4H) m-Phenylene- δ9.7 (s, 2H), δ7.6-7.2 (4H) D₂O diamine m-Xylylenediamine δ9.9 (s, 2H), δ7.5 (ph, 4H), δ4.1 (s, 4H) DMSO Hydrazine δ9.7 (s, 2H), D₂O 1-Urea δ10.1 (s, 1H), δ7.5 (s, 5H) DMSO 2-Urea δ10.2 (s, 1H), δ8.2 (s, 6H) DMSO Thiocarbohydrazide δ9.8 (s, 2H) D₂O Melamine 1/3 δ9.8 (s, 3H), δ6.5 (s, 10H) DMSO Melamine 2/3 δ7.3 (s, 2H), δ4.6 (s, 8H) DMSO Melamine 1/1 δ8.0 (s, 1H), δ3.4 (s, 4H) DMSO

TABLE 8 NMR Analysis Secondary and Tertiary Amine Salts Amine Salt (ppm) Solvent Dimethylamine δ9.7 (S, 1H), δ2.4 (s, 6H) D₂O Piperazine δ9.7 (s, 1H), δ3.85 (s, 8H) D₂O Piperidine δ9.7 (s, 1H), δ3.4-3.0 (t, 4H), D₂O δ2.0-1.6 (s, 6H) Diphenylamine δ10.0 (s, 1H), δ7.2 (t, 4H) DMSO δ7.1 (d, 4H), δ6.8 (t, 2H) Trimethylamine δ9.9 (s, 1H), δ2.8 (s, 9H) DMSO Hexamethylene- δ9.7 (s, 1H), δ4.7 (s, 12H) D₂O tetramine

The above results reveal that the 1,5′-bitetrazole of the invention is a novel substance.

EXAMPLE 6

The crystals of 1,5′-bitetrazole piperazine salt obtained in Example 1 were finely ground in a mortar, added to a low-density polyethylene (melting point: 90° C.) in a proportion of 5 wt. % relative to the polyethylene, and extrusion-molded using an extruder at a resin temperature of 140° C., giving master chips having a diameter of about 3 mm and a length of about 3 mm.

EXAMPLE 7

The crystals of 1,5′-bitetrazole guanidine salt obtained in Example 4 were finely ground in a mortar, added to an acrylonitrile-styrene resin (AS resin; Vicat softening point: 104° C.) in a proportion of 5 wt. % relative to the resin, and extrusion-molded using an extruder at a resin temperature of 140° C., giving master chips having a diameter of about 3 mm and a length of about 3 mm.

EXAMPLE 8

The master chips obtained in Example 6 were added to a polypropylene resin to be molded, in a proportion of 2 wt. % relative to the resin, and injection-molded at 220° C. using a test mold measuring 3 mm thick, 100 mm wide and 100 mm long and having ribs with three different widths of 4 mm, 5 mm and 6 mm. The obtained molded article was compared with a blank molded article containing no foaming agent. The blank article had sinkmarks on the surface opposite to the ribbed surface and was commercially unacceptable, whereas the molded article containing the foaming agent of the present invention was completely free from sinkmarks.

EXAMPLE 9

The master chips obtained in Example 7 were added to a polyacetal resin to be molded, in a proportion of 2 wt. % relative to the resin, and injection-molded at 210° C. using a test mold measuring 3 mm thick, 100 mm wide and 100 mm long and having ribs with three different widths of 4 mm, 5 mm and 6 mm. The obtained molded article was compared with a blank molded article containing no foaming agent. The blank article had sinkmarks on the surface opposite to the ribbed surface and was commercially unacceptable, whereas the molded article containing the foaming agent of the present invention was completely free from sinkmarks and had a smooth skin layer.

COMPARATIVE EXAMPLE 1

Master chips were prepared in the same manner as in Example 6 except for using 20 wt. % of ADCA in place of the crystals of 1,5′-bitetrazole piperazine salt, and added to a polypropylene resin to be molded, in a proportion of 2 wt. % relative to the resin. The mixture was injection-molded at 220° C. using a test mold measuring 3 mm thick, 100 mm wide and 100 mm long and having ribs with three different widths of 4 mm, 5 mm and 6 mm. The obtained molded article was compared with a blank molded article containing no foaming agent and with the molded article of Example 8. The molded article obtained in this comparative example was satisfactorily foamed but had so-called “silver blisters”, i.e., air bubbles on the surface. Also, the mold was severely contaminated when repeated test molding was carried out.

COMPARATIVE EXAMPLE 2

Master chips were prepared in the same manner as in Example 7 except for using 20 wt. % of ADCA in place of the crystals of 1,5′-bitetrazole guanidine salt, and added to a polyacetal resin to be molded, in a proportion of 2 wt. % relative to the resin. The mixture was injection-molded in the same manner as in Comparative Example 1. The obtained molded article was compared with a blank molded article and with the molded article of Example 9. The molded article obtained in this comparative example was satisfactorily foamed but had so-called “silver blisters”, i.e., air bubbles on the surface, and did not have clearly defined edges. Also, the mold was severely contaminated when repeated test molding was carried out. 

What is claimed is:
 1. A substituted ammonium salt of 1,5′-bitetrazole represented by formula (1):

wherein Tz⁻ represents

R¹, R², and R³ are the same or different and each represent a hydrogen atom; C₁₋₁₀ alkyl which may be substituted by amino, di(C₁₋₄ alkyl) amino, C₁₋₈ alkoxy, hydroxy or phenyl; C₃₋₂₀ alkenyl; phenyl; —C(═NH)NH₂; —C(═NH)NHNH₂; —C(═NH)NHCN; triazolyl; amino; carbamoyl; triazinyl which may be substituted by amino and methyl; —NHCS;

or —R⁴—NH₃ ⁺ Tz⁻ wherein Tz⁻ is as defined above, R⁴ represents a single bond, C₂₋₆ alkylene, phenylene, —CO— or

when R¹ is a hydrogen atom, R² and R³ may be taken together with the nitrogen atom to which they are attached to form a 5— to 7—membered saturated heterocycle; when R¹ is a hydrogen atom, R² and R³ may be taken together to form

and R¹, R² and R³ may be taken together to form 